Secondary relaxation temperature

{
  "id": "MLC-T-CHM-010630",
  "term": "Secondary relaxation temperature",
  "field": "Chemistry",
  "definition": "A characteristic temperature below the glass transition temperature at which localized molecular motions within a polymer become unfrozen. These motions involve small segments of the polymer chain or side groups, rather than the large-scale cooperative movements associated with the glass transition. This temperature is detected as a peak in the mechanical loss modulus or loss tangent versus temperature curve.",
  "subject": "Polymer",
  "see_also": [
    "loss modulus",
    "loss tangent"
  ],
  "references": [
    "PAC, 2013, 85, 1017. 'Glossary of terms relating to thermal and thermomechanical properties of polymers (IUPAC Recommendations 2013)' on page 1038 (https://doi.org/10.1351/PAC-REC-12-03-02)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/secondary-relaxation-temperature/"
}